In Design Extender, The Google map tool has been updated to use the New Map V3 API. In the Map v3 API a key is no longer required. It is still recommended to use one though in order to track usage.

With the new keys, they are no longer tied to a specific domain, in the API Center, you can set the domains that the key will be valid for. it will no longer be necessary to have a separate key for each domain.